Added Project API.
Removed unnecessary requirement of project_id param on need API get method. This is more consistent with CiviCRM conventions
(calls to API with no params generally return all records). It also resolves the "Mandatory key(s) missing from params array: project_id"
error on civicrm/event/manage/volunteer?reset=1&action=update&id=n.
Merge pull request #65 from fjg-conflux/project_api

Added Project API, fix for Need API.